Effect of prayer on rainfall in Georgia

On Tuesday, November 13, 2007, Sonny Perdue, the Governor of Georgia, led a group of approximately 250 persons, including many state officials, in a prayer for rain on the steps of the state capitol in Atlanta.1 Georgia had been suffering an extreme drought, and the level of Lake Lanier, an important water reservoir near Atlanta, had been decreasing dramatically over several months. Governor Perdue believed that a divine intervention was necessary and so he boldly asked God to bring rain.

It rained. The author, Gary J. Whittenberger, compares the amount of rain before and after the prayer with rainfall in the previous ten years to show that it wasn't an unusual increase in rainfall, especially considering that the prayer was done during a time of drought. As Allan Donald comments, regression to the mean explains the increase in rain all by itself.

Interestingly, several readers belittle the article, saying that it is ridiculous to even discuss the idea of praying for rain, that if people want to believe in the power of prayer, then you should just let them (note this is the Skeptic Magazine!), and that it’s silly and counterproductive to spend time "on an analysis that the author knew ahead of time couldn’t prove anything." The last remark I find quite true. There is no way that even a torrent of water the minute the prayer was over could convince me that the prayer was resposible, as long as there are other and better hypotheses. However, apparently, for the citizens of Georgia, less would suffice.

Many Georgians considered Perdue a hero and thought that his prayer had influenced God to increase rainfall to the drought stricken vicinity of Atlanta.

And therefore I think this article is not such a bad idea after all. Let the Georgians read it, and perhaps some of them will realize that the increase in rainfall coinciding with the prayer does not need to be an act of God.

Pleiotropy comes from the Greek πλείων pleion, meaning "more", and τρέπειν trepein, meaning "to turn, to convert". It designates the occurrence of a single gene affecting multiple traits, and is a hugely important concept in evolutionary biology.

I'm a postdoc at UC Santa Barbara.

All Many aspects of evolution interest me, but my research focus is currently on microbial evolution, adaptive radiation, speciation, fitness landscapes, epistasis, and the influence of genetic architecture on adaptation and speciation.